1、SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirelyvoluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefro
2、m, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions.Copyright 2000 Society of Automotive Engineers, Inc.All rights reserved.Printed in U.S.A
3、.TO PLACE A DOCUMENT ORDER: (724) 776-4970 FAX: (724) 776-0790SAE WEB ADDRESS: http:/www.sae.org400 Commonwealth Drive, Warrendale, PA 15096-0001AEROSPACE INFORMATION REPORTAIR1335REV.AIssued 1975-01Revised 2000-03Ramp De-IcingFOREWORDChanges in this revision are format/editorial only.TABLE OF CONTE
4、NTSINTRODUCTION 21. SCOPE .42. REFERENCES .43. DE-ICING WEATHER.43.1 Season and Temperature 43.2 Heat .44. SURFACE DE-ICING FLUID55. RAMP DE-ICING 56. THE FUTURE OF DE-ICING67. WHY DE-ICING? 87.1 De-Icing .87.2 Why De-Ice? 87.3 Ice-Accretion87.4 Icing Conditions for Jets 108. IMPROPER DE-ICING .108.
5、1 “Aileron and Rudder Nibble vs Vibration Enroute“ - An Actual Occurence108.2 Reaction. 11APPENDIX A .12SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/AIR1335A SAE AIR1335 Revision A- 2 -INTRODUCTIONA. REPORT ON DE-ICINGThis br
6、ief report attempts to summarize many different factors and it should be noted that the figures are not exact and should only be taken as “rule of thumb“ figures; there are many, many exceptions to them. De-icing is a long way from an exact science and is actually a very rough science, with very lit
7、tle having been written about it. Much of the following information has been received from Air Canada and we wish to give credit and thanks to Air Canada for their help. De-icing probably affects Air Canada more than any other airline in the western world, consequently, they are probably more concer
8、ned with the problem than other airlines. In recent years, however there has been an increasing awareness by all airlines flying in the northern hemisphere and, consequently, the management of all of these airlines are much more concerned with the possibility of delays, particularly with the increas
9、ed travel and increased size of the aircraft.B. BRIEF HISTORY OF RAMP DE-ICINGAs recently as 1957, the only type of de-icing or snow removal equipment available to many airlines was manual or if a hangar was available, then the aircraft could be moved into the hangar, and the snow or ice washed off
10、with water from the fire hydrant. A manual method of removing snow was either by the use of brooms, which were very dangerous both to personnel and to aircraft, or by tying knots in a rope with rags in the knots. The rope would then be thrown over the wing and one man on either end would pull the ro
11、pe back-and-forth, in this way loosening up the snow and ice and partially cleaning the wings. It was fairly common in the 1950s to have a plane towed to a hangar and have the snow washed off with a fire hydrant hose and then someone on a stepladder with a bucket of glycol would spray on a protectiv
12、e coating. This procedure was improved by having a small, air-cooled engine driving a pump and a tank of glycol, all supported by a forklift and the operator could be maneuvered around the aircraft. There were many other such methods, even a simple platform, for the operator to stand on, mounted on
13、a truck. During the 1950s, Canadas role in North American defense was one of having fighter aircraft at various bases across the northern part of North America. These fighters were to become airborne in the event of an attack by a foreign power. The threat was ever present of catching the fighter ai
14、rcraft with snow on the wings and snow on the runway, preventing the aircraft from interrupting the possible attack. This situation caused activity to obtain equipment to not only wash the snow and ice off of the wings of the aircraft quickly but also to clean the runways quickly. Possibly the fore-
15、runner of sophisticated de-icers was developed for the Canadian Air Force in the mid-1950s in the form of a small, three-wheeled vehicle with a single boom which would not only elevate but also traverse between the wheels and having a tank which was heated electrically and a pump to dispense the hea
16、ted fluid. At the same time, the U. S. Air Force had a requirement for a decontaminating vehicle which could spray hot, decontaminating fluid on a bomber in the event of its returning from a nuclear bombing raid and having been subjected to nuclear fallout. A large number of these vehicles were buil
17、t, however, the device turned out to have all of the basic ingredients of a sophisticated de-icer, insofar as it had tanks, pumps, closed flame heaters and the aerial apparatus. These machines were too costly for the commercial airlines and it was only Air Canada that bought any, the cost justified
18、by using them for flight maintenance as well as de-icing. Equipment needs changed and, with the size of aircraft increased, this small, three-wheel machine was too small, too slow and provided insufficient heat for a busy station.SAE AIR1335 Revision A- 3 -Because of the inadequacies of the small de
19、-icer, the next generation device was a truck-mounted unit which, of course, had much higher ground speeds, larger tanks, larger pumps and closed flame heaters similar to those used by the U. S. Air Force. In all of the de-icers mentioned to this point, 10 gallons per minute from a nozzle was consid
20、ered a fairly large flow. In the early 1960s, a three wheel vehicle type de-icer was developed in the United States which had much larger tanks, larger pumps and an open flame gas fired heater. This unit was produced in quantity and was quite satisfactory except for its ground speed. In the mid-1960
21、s, the quantity of glycol sprayed from the nozzle increased dramatically and it was proven that the larger gallonages from the single nozzle transmitted more BTUs to the wings, more efficient in heat transfer and in time to de-ice an aircraft. The increased use of glycol was accepted. In the meantim
22、e, Air Canada was experiencing higher costs than any other airline because of many more days of de-icing weather and because of the increase in the size of planes and in the frequency of flights. A third generation of aircraft de-icers was ordered, which, of course, had larger tanks, larger pumps, h
23、igher pumping pressures, higher aerial devices and closed flame heaters.In early 1968 the Air Transport Associations committee on de-icing and aircraft servicing drew up specifications for a fourth generation of de-icers which came into being with the introduction of the 747. The fourth generation w
24、as very much larger and truck mounted, with a minimum 1500 gallon tank size and the ability of “instant heat“. This would give them the ability to take the fluid from a partly heated tank and discharge it at the maximum temperature directly on to the aircraft. Any type of de-icer with a hot tank and
25、 a pump and some sort of aerial device could de-ice the first plane but when additional de-icing was necessary and the vehicle had to be refilled with cold glycol, a large amount of heat was needed in order to heat fluid to get back to work quickly without having to sit back in a corner and heat up.
26、 This also brought in the importance of a closed flame heater.This fourth generation of de-icer is now widely used and is most effective on the large jets as well as the large number of smaller jets.The four generations of de-icers are roughly as follows:First - Small three-wheeled self-propelled el
27、ectrical heaters.Second - Larger three-wheeled self-propelled open flame gasoline fired heaters, larger pumps.Third - Truck mounted, medium sized tanks, both open and closed flame gasoline fired heaters, larger pumps.Fourth - Large truck mounted, large tanks, large closed flame gasoline fired heater
28、s with instant heat, large pump.SAE AIR1335 Revision A- 4 -1. SCOPE:The specific purpose of this AIR is to provide general background information to better acquaint those who are involved with ramp de-icing of aircraft.Because the wide variance of atmospheric conditions at different airports, as wel
29、l as at any individual airport, the figures given are of a general nature only and are to be taken as a very rough guide to the various factors concerned with ramp de-icing.2. REFERENCES:AIRCRAFT ICING, FLIGHT OPERATIONS, VOL. LVIII, Dec. 1963DOT Amendment No. 9 to CIR-3450, OBS-300, 1 July 1961, MA
30、NOBS, fifth edition.P-52, 53, Our American Weather, Geo. H. T. Kimble, McGraw-Hill Book Company, Inc., New York, 1955.3. DE-ICING WEATHER:3.1 Season and Temperature:Generally, the airlines expect the de-icing season to start October 15 and go through to April 15. These dates, of course, have to be m
31、odified depending upon the part of the country, as early frosts are quite common as early as September 15 and late snowfalls occur in certain areas as early as September 15 and as late as May 15.Mainly, de-icing temperatures are between 20 - 40 F (-6.7 - 4.4 C). The operators jokingly say that de-ic
32、ing is usually necessary at night, on a weekend or on a holiday, particularly, when skilled personnel are usually off duty. Storms do often happen on Thanksgiving weekend, Christmas and New Years. The general rule of thumb is that de-icing weather is reasonably light in the Fall but January and Febr
33、uary, and in many areas March, are bad months. There are some areas where they can expect to be de-icing as much as one out of every three days during the bad months.3.2 Heat:The next most important factor is heat. Many operators will tell you that this is the main ingredient and the de-icing fluid
34、is merely the means of transferring the heat onto the wing and melting the ice. Because of the heat there is only a thin film of glycol left on the wings and there is a possibility of larger amounts of fluid being left on the wings which will cause problems in flight. Therefore, it is important that
35、 if you are transferring heat on to the wings, then you should do it by heating the fluid so that it contains the most number of BTUs per gallon but also to put on a stream which will transfer it with a minimum loss of heat to the air. A fine fog coming out of the nozzle will cool the fluid off very
36、 rapidly and practically no heat will get transferred to the wings or aircraft surfaces. A solid stream is the most efficient means of transferring this heat. The further you are away from the aircraft, of course, the more heat loss to the environment; the closer you are, the more danger there is of
37、 a solid SAE AIR1335 Revision A- 5 -3.2 (Continued):stream of high gallonage fluid damaging the aircraft. A rough guideline is that the nozzle should never be closer than about 10 ft (3 m) from any aircraft surface and then the stream should be directed in such a manner that it is hitting the aircra
38、ft surfaces at a very low angle. A very rough figure is that the heat transfer is only about 25% efficient so that you can see the need for putting as many BTUs as possible into the smallest number of gallons. A safe heat is around 180 - 190 F (82 - 88 C). This presents a problem since pumping hot g
39、lycol from a tank shortens the life of the pump. When the pump sucks the fluid from the tank, it lowers the pressure and lowers the boiling point of the fluid and, consequently, the pump then will be pumping partial vapor and cavitating. A reasonably safe figure is to have the tank around 140 F (60
40、C) and then using a coil type of heater to add the heat to it after the fluid has left the pump and before coming out the nozzle. This will insure a much longer life for the pump. It does, of course, require considerably larger heaters but the heat capacities specified by the A.T.A. committee is sui
41、table for the capability of taking semi-heated fluid and heating it up during the last pass before going out of the nozzle. The cost of heating the fluid is very low in comparison with the cost of the de-icing fluid and a rough rule of thumb is that you get about 100,000 BTUs at the nozzle for every
42、 gallon of gas burned. 2,000,000 BTUs per hour heating capability would burn approximately 20 gallons of gas per hour at a cost of less than $5.00 per hour. This is, of course, if it were heating continuously at its highest output.4. SURFACE DE-ICING FLUID:A de-icing fluid is generally referred to a
43、s “glycol“ because most de-icing fluids are made up of a mixture of ethelyne glycol, propylene glycol, and then certain additives, such as a corrosion inhibitor, and then a wetting agent that would contain material similar to glucose, which makes the fluid adhere to the appropriate surfaces to give
44、it the anti-icing quality while it taxis out to the end of the runway. There are, of course, many different de-icing fluids on the market and several manufacturers attempt to keep their formulations secret. The main ability of the de-icing fluid is not to freeze and to run off of the aircraft surfac
45、es but still to leave a thin film to provide anti-icing qualities.Surface de-icing fluid comes basically from an ethylene stock. This, of course, is a by-product of natural gas as well as crude oil and certainly that produced from natural gas was almost considered a waste product up until a relative
46、ly few years ago. It is now widely used in synthetic fibers which are presently taking 1/2 of the ethylene supply. It is anticipated that this market will grow much faster than the market for surface de-icing fluid with the result that the cost of the fluid will increase very noticeably as supplies
47、diminish and demand increases.5. RAMP DE-ICING:After analyzing conditions under which de-icing generally is required, it is a coincidence that many of the figures come out to be a 75 to 25 ratio. Some examples are listed below and, again, all of these figures are approximate.First of all, 75% of all
48、 de-icing comes between the 24 - 38 F (-4.4 - 3.3 C) range. The balance, or 25% of de-icing, is done outside this range.SAE AIR1335 Revision A- 6 -5. (Continued):The next item is that 75% of de-icing work is done when the wind velocity is between 0 and 20 miles per hour and, of course, the other 25%
49、 is when the wind is in excess of 20 miles per hour.Another interesting figure is that 75% of de-icing fluid is used in wind velocities under 20 miles per hour.Still another interesting figure on fluids is that 75% is used on originating flights and 25% on through flights.75% of de-icing weather is sticking snow, frost, or freezing rain and 25% of the weather is light, medium and heavy snow.In 75% of de-icing conditions, heat is needed and in 25% it is not needed.Another very important ratio is that more than 90% of the cost of de-icing operations is for the
